function check_color()
{
	var size=$("select[name='velkost']").attr("value");
	var color=$("select[name='farba']").attr("value");
	var x='';
	var change_color=false;
	for(row in matrix)
	{
		if(matrix[row][size]) $("select[name='farba'] option[value='"+row+"']").removeAttr("disabled");
		else 
		{
			$("select[name='farba'] option[value='"+row+"']").attr("disabled","disabled");
			if(color==row) change_color=true;
		}
	}
	if(change_color)
	{
		var changed=false;
		$("select[name='farba'] option").each(function(){
			if(!$(this).attr("disabled") && !changed) 
			{
				$(this).attr("selected","selected");
				changed=true;
			}
		});
	}
}

$(document).ready(function(){
	$("select[name='velkost']").change(check_color);
	check_color();
});